Mechanisms of neurologic deficits and mortality with carotid endarterectomy

J. F. McKinsey, T. R. Desai, H. S. Bassiouny, G. Piano, J. P. Spire, C. K. Zarins and B. L. Gewertz
Department of Surgery, University of Chicago, Ill., USA.

OBJECTIVE: To evaluate the incidence and etiology of perioperative complications of carotid endarterectomy. DESIGN: Retrospective review of carotid endarterectomies performed over 13 years. Risk factors, indications, results of electroencephalographic (EEG) monitoring, and outcomes were evaluated. SETTING: University medical center. PATIENTS: Three hundred sixty-seven consecutive primary carotid endarterectomies were performed on 336 patients. Indications for operation included transient ischemic attack (48.5%), asymptomatic stenosis (24%), stroke (17%), nonlateralizing ischemia (9.5%), and stroke-in-evolution (1%). MAIN OUTCOME MEASURES: Postoperative neurologic deficits (permanent and transient) and deaths were correlated with preoperative symptoms, probable mechanism of the neurologic event, intraoperative EEG changes, and the use of intraoperative shunts. RESULTS: Four new permanent neurologic deficits (1.1%) and one transient postoperative deficit were noted. Of the five deficits, three were related to undiagnosed intraoperative cerebral ischemia and two were related to perioperative emboli. Three perioperative deaths (0.8%) occurred: two of myocardial infarction and one of an intracerebral hemorrhage from a ruptured arteriovenous malformation. Intraoperative EEG tracings for the most recent consecutive 175 procedures were analyzed. Shunts were used in 45 patients (26%), 38 of whom demonstrated significant EEG changes with carotid clamping. CONCLUSIONS: Carotid endarterectomy can be performed with a low risk of stroke (1.1%) and death (0.8%). Stroke was due to cerebral ischemia or embolization. With meticulous surgical technique, death is due to myocardial ischemia and not neurologic events.